Implement enquoteIdentifier() and isSimpleIdentifier() from JDBC 4.3

Grammar documentation change

Integer/Long.compare(x, y) can be used to compare primitive values

Grammar documentation: Extracting columnName from "Column Definition" for reuse in ALTER TABLE ALTER COLUMN.

Fixes in tests

Fix for issue #725: FilePathMem.tryLock() fails since Java 9

Use dummy FakeFileChannel as suggested by Noel Grandin to fix
memory and ZIP file systems.

Clean up LocalDateTimeUtils

Use StringBuilder instead of StringBuffer

DROP TABLE RESTRICT shouldn't drop foreign keys in other tables

Conversion methods provided by JDK are not used anymore for many reasons.

Assorted minor changes

This call is not required before close() and it will prevent closing of writer
if write fails for some reason.

Issue #638: Oracle mode: incompatible regexp back-reference syntax

Partial fix for #495